Documentation additions and changes for SimpleMatrix

[JozsefKutas]

This PR contains various documentation additions/changes for SimpleMatrix:

• The main addition is a set of tables listing the methods in SimpleMatrix/SimpleBase with brief descriptions. Unlike the javadoc summary table, this groups and sorts methods according to functionality. Given that SimpleMatrix/SimpleBase combined have ~100 methods, it can be difficult to find the method you need when looking through an ungrouped alphabetical list.

• Added missing javadoc for a few methods.

• References to an internal DMatrixRMaj have been replaced by references to an internal matrix where appropriate.

• Replaced "a.k.a." by "or" to avoid the javadoc summary cutting off early (it assumes a period and space terminates the first sentence).

[JozsefKutas]

Btw, for the SimpleMatrix#random_XXXX static factory methods, I say that values are drawn from a uniform distribution inclusive of the lower bound and exclusive of the upper bound, but the docs in RandomMatrices_XXXX say the distribution is inclusive on both ends. I think this is a mistake? Not that it makes any difference in practice.

[lessthanoptimal]

Just glanced at this and it looks great. It will probably be a week before I can do a proper review of everything since my day job is keeping me very busy at the moment.

[JozsefKutas]

No problem, I've been in the same position for a while now.